I'm meeting a friend in London next week. We shall rendezvous at around 11:30am and have an event booked at 18:30. We can dine after the event so don't necessarily need to allow time to eat during the afternoon, but a stop for coffee / cake would probably be nice.
Any ideas for something fun and a bit different to do for the afternoon? We both have 'done' a lot of the usual touristy things. We're in our forties and both fit and well for getting around etc.